Abstract : Public Law 91-611, through Section 101 of the 1970 Rivers and Harbors Act, authorized a plan of improvement to deepen the existing navigation channels to the Port of Baltimore from 42 ft to 50 ft and to extend the channels to the natural 50-ft-depth curves. Tests on the Chesapeake Bay hydraulic model were conducted to specifically investigate possible changes in the hydrodynamic characteristics of velocity, salinity, and tidal elevations associated with the proposed channel enlargements. Changes in these parameters can result in changes to estuarine circulation and dynamics, sedimentation rates and patterns; can effect biological communities and distributions; and can affect dispersion of pollutants and nutrients.